The aim of this work is to evaluate the impact of a local policy change (i.e., the Minneapolis Staple Food Ordinance) that establishes minimum stocking criteria for a wide array of healthy foods as a requirement of food store licensing. Recent calls to action from the CDC, the Institute of Medicine and other authorities have identified improving access to healthy foods as a primary strategy for local governments to use in advancing obesity prevention efforts, but policy initiatives in this area have been limited. In this study, the impact of the Minneapolis Staple Food Ordinance will be evaluated by a multidisciplinary team of partners, including academic researchers, local government officials and community leaders. Our local NOPREN team will assess changes in: (a) food environments among small, urban food stores, including availability, promotion, advertising, quality, price, and placement of both healthy and unhealthy foods and beverages, and (b) nutritional quality of consumer purchases at small food stores, including assessment of energy density and calories via customer intercept surveys and direct observation of purchases. These changes will be assessed pre-policy implementation, as well as 12- and 24-months post-policy implementation, in two Minnesota cities: Minneapolis and St. Paul, (our control community). The proposed scope of work for this project is important because its takes advantage of a unique opportunity to evaluate an innovative local policy addressing a recommended action area for obesity prevention that aligns with key recommendations by leading obesity prevention authorities. To our knowledge, the Minneapolis Staple Food Ordinance is the only policy of its kind in the US, and as such it could serve as an important model policy for other local governments if it is successful.